Its mission complete, the spacecraft Philae has sent its last data, finishing off a historic touchdown rendezvous with a comet, the first in human history.

Scientists think that comets were formed early in the history of the universe and that data-gathering from comets can help human understanding of the very early years after the Big Bang.

The robotic Philae was the landing part of the Rosetta mission, which will continue to orbit the comet 67P/Churyumov-Gerasimenko (or Comet C-G) for another year or so. The Rosetta spacecraft launched in 2004 and performed various other tasks before launching its lander Philae into the comet, including making a close flyby of Mars and a few significant asteroids, sending back data along the way.

The highlight was the landing on the comet. The plan was for Philae to deploy anchoring harpoons to assist in landing on the comet's surface. That didn't happen, but the tiny spacecraft did land on the surface, after a few bounces, and came to rest about half a mile from its original target. Philae drilled 10 inches deep into the comet's surface and used other sensors to gather information, all of which was sent back to Earth.

Philae was last heard from just before its batteries drained. Scientists are hoping that as the comet approaches the Sun, the solar-powered generators will be recharged. Rosetta will continue its orbit, however, until well into 2015. Another important experiment is for Rosetta to observe how the icy contents of a comet are transformed when it gets nearer the Sun.

The Rosetta spacecraft is named after the Rosetta Stone, a stone from ancient Egypt that has the same inscription in three languages and was used to deciper hieroglyphics. The Philae lander is named after the Philae obelisk that has an inscription in Greek and hieroglyphics and was also used to help deciper hieroglyphics.